One of the key questions concerning frustrated lattices that has lately emerged is the role of disorder in inducing spin-liquid-like properties. In this context, the quantum kagome antiferromagnet YCu 3 (OH) 6 Cl 3 , which has been recently reported as the first geometrically perfect realization of the kagome lattice with negligible magnetic/nonmagnetic intersite mixing and a possible quantum-spin-liquid ground state, is of particular interest. However, contrary to previous conjectures, here we

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... show clear evidence of bulk magnetic ordering in this compound below T N = 15 K by combining bulk magnetization and heat capacity measurements, and local-probe muon spin relaxation measurements. The magnetic ordering in this material is rather unconventional in several respects. First, a crossover regime where the ordered state coexists with the paramagnetic state extends down to T N /3 and, second, the fluctuation crossover is shifted far below T N . Moreover, persistent spin dynamics that is observed at temperatures as low as T /T N = 1/300 could be a sign of emergent excitations of correlated spin loops or, alternatively, a sign of fragmentation of each magnetic moment into an ordered and a fluctuating part.